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Slip Speed and Drive Torque Planning of Multivariable Controller for an Electrified Vehicle with Dual Clutch Transmission
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on September 15, 2020 by SAE International in United States
The demand for electrified vehicles is increasing due to increased environmental pollution regulations and the increasing demand for vehicles with high energy efficiency. In response to these demands, research on electrified vehicles equipped with dual clutch transmission (DCT) has been actively conducted to improve the energy efficiency and ride quality of the electrified vehicle, maximizing the acceleration performance and increasing the maximum speed. However, since DCT requires clutch to clutch shifting, it is difficult to control drive torque and slip speed by using two clutch actuators. To solve this problem, research on multivariable shift controllers using power source torque and clutch actuator as inputs has been conducted. However, this study chose the heuristic planning method to control the two outputs. Because slip speed and drive torque are coupled, heuristic planning can create unnecessary control inputs or reduce shift control performance. Therefore, this paper proposes reference planning of slip speed and drive torque for DCT shift control of electrified vehicles using the multivariable controller. Specifically, the powertrain modeling of the electrified vehicle satisfies the dynamics and configures a reference constraint consisting of power source input, slip speed, and output torque. Therefore, the slip speed is unique when planning the control intervention of the power source input and the output torque reference. To verify the planning method proposed in this paper, an electrified powertrain simulator designed with a multivariable controller (H-infinite) is constructed with MATLAB/SIMULINK. Then, heuristic reference planning method of the previous study and the proposed method in this paper simulated gear shift scenario in a vehicle composed of the same shift controller and powertrain. As a result, the energy consumption of the clutch actuator was reduced by about 10% and the jerk was reduced by about 20%.